The India Diet and Health Study is a large, multi-regional prospective cohort study to assess the relationship between diet and the development of cancer. With the aim of enrolling one million study participants from three different regions of India, this project is currently in the pilot stage where the feasibility of establishing such a large, complex cohort is being thoroughly investigated. Study participants will complete multiple questionnaires to obtain data on several areas: dietary intake, physical activity, medical and occupational history, tobacco and alcohol use, and other demographic information. Biospecimens such as blood, urine, and toenail clippings will also be collected for analysis.